Loom reed

ABSTRACT

A loom reed is provided with flexible, extrudable thermoplastic adhesive frame members which also serve as dent wire spacing means. Suitable thermoplastic adhesives include ethylene copolymers and polyamides.

United States Patent 1191 1111 3,746,053

Crain July 17, 1973 [541 LOOM REED 2,869,587 1/1959 Schmidt 139/192 2,989,088 6/1961 Schmidt .1 [75] Inventor: George W. Cram, Wh1te Bear Lake, 2,643,684 6/1953 Taylormmu 2,914,094 11/1959 1111 6111115... [73] Assigneez Minnesota Mining and 3,189,056 6/1965 Parks 139/192 xfi' Paul 1 011121019 PATENTS OR APPLICATIONS 1,146,831 5/1957 France 139/192 Flledl 1972 614,713 1/19'61 Italy [21] APP] NO; 222 835 564,283 2/1958 Belgium 139/192 Related US. Application Data P m Exam n James Kee Chi [63] Continuation-in-part of Ser. No. 81,054, Oct. 15, n my 1 er 1970 v Attorneyl(inney, Alexander, Sell, Steldt & Delahunt [52] US. Cl. 139/192 511' 1111. C1 D03d 49/62 [571 ABSTRACT [58] Field of Search 139/192; 29/467,

A loom reed is provided with flexible, extrudable thermoplastic adhesive frame members which also serve as References Cited dent wire spacing means. Suitable thermoplastic adhesives include ethylene copolymers and polyamides. UNITED STATES PATENTS 3,154,110 10/1964 Rockett 139/192 4 Claims, 2 Drawing Figures a l Vy Patented July 17, 1973 FIG. 2

LOOM REED This application is a continuationin-part of my copending application Ser. No. 81,054.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to loom reeds and, more particularly, to loom reeds having thermoplastic adhesive frame members.

2. Description of the Prior Art Loom reeds are used in the textile industry as guides for various fibers in the weaving operations. The loom reeds hold and separate the warp yarns which are continuously drawn through the reeds while the weft yarns are woven through the warp yarns. As part of this weaving process, the loom reed is constantly reciprocated so as to position the weft yarns against each other.

The loom reeds themselves are ordinarily comprised of a plurality of dent wires in spaced parallel relationship, the ends of the dent wires being firmly fixed within rigid frames. Typical of such loom reeds are those having metal frames wherein the ends of the dent wires are firmly soldered to wrapped wire spacing means and metal bars, e.g., as the basic loom reed structure described in US. Pat. No. 3,154,110. Other conventional rigid loom reed structures, typically known as pitch band reeds, are described in US. Pat. Nos. 2,383,140; 2,870,796; and 2,941,552. The pitch band reed frame is ordinarily of lesser quality than the metal reed frame and it consists of wooden strips between which the dent wires are disposed while string is used to wrap the wooden strips together and to also space the dent wires from one another. After the string has been wrapped around the wooden strips, pitch is ordinarily poured over the wooden strips and the string to serve as a binder.

While such rigid loom reeds have been widely used for decades, several inherent disadvantages are apparent in such constructions. For example, because the dent wires are rigidly secured at their ends, there is a high bending stress at their junction with the anchoring solder or frame. Thus, the constant vibration and shock imparted to the loom reed during the weaving operation will loosen or misalign the dent wires because the dent wires are incapable of flexing or absorbing the shock. Also, loom reeds having rigid frames must be carefully handled so as to avoid twisting, dropping, or jolting them.

There are also many drawbacks associated with the preparation of loom reeds having rigid frames. For example, when using soldering operations one must necessarily use preliminary cleaning and fluxing steps and must handle high temperature molten solder. Uneven setting and cooling of the solder may cause misalignment of the dent wires, thus requiring subsequent realignment of the dent wires to compensate for unevenness in spacing. With respect to the preparation of pitch band loom reeds tedious and often imprecise wrapping of the wooden frames with string may easily result in uneven spacing of the dent wires.

Moreover, such rigid loom reed constructions do not allow for ready removability of damaged dent wires if the need arises. Rather, such rigid loom reed constructions must be completely disassembled for repair or must be entirely replaced with a new loom reed.

More recently, there has been disclosed (see US. Pat. Nos. 2,869,587 and 2,989,088) a loom reed in which a curable or polymerizable elastomer is employed within a metal frame to anchor the ends of the dent wires. Although such loom reed constructions allow side-to-side flexing of the dent wires and eliminates the problems associated with the conventional soldering operations, such loom reed constructions do not allow for ready removability or replacement of individual dent wires. Furthennore, such constructions do not eliminate the need for expensive metal supporting strips for the curable elastomer and the ends of the dent wires.

Another approach toward eliminating some of the problems attendant with rigid metal frames is that described in US. Pat. No. 3,l54,l 10 wherein a removable, shock-absorbing, plastic loom reed rib guard is slipped over a conventional rigid metal frame for the purpose of absorbing impact and vibration and preventing distortion of the dent wires and the metal frame. Although this approach may eliminate vibration and distortion of the dent wires, it does not allow for ready removability or replacement of individual dent wires, nor does this approach lessen the expense or the practical problems attendant with the preparation of loom reeds.

Other related approaches of a similar nature are described in Belgian Pat. No. 564,283 and Italian Pat. No. 614,713 wherein the ends of the dent wires are placed between transversely extending cross bars after which metal wire or thread is wrapped around the cross bars and between the dent wires so as to firmly secure, support, and space the ends of the dent wires. Subsequently, the ends of the dent wires are embedded and secured in a plastic frame. However, such approaches do not provide for ready removability or replacement of individual dent wires. Furthermore, because the ends of the dent wires are firmly secured between the cross bars with metal wires wrappings, the resulting loom reed construction is still rather rigid in nature and the amount of flexing which it can undergo without damage thereto is accordingly limited. Although such approaches to loom reed constructions have eliminated the need for expensive metal frames, these approaches are still reliant upon the tedious processes of wrapping and securing the ends of the dent wires between cross bars.

French Pat. No. 1,146,831 suggests that loom reed frames may be made of synthetic resin (thermosetting or easily pourable thermoplastics) with no need for supporting cross bars or special spacing means for the ends of the dent wires. However, use of thermosetting synthetic resins does not allow for ready removability or replacement of individual dent wires. Furthermore, those thermoplastic resins which are easily pourable are necessarily less than 1,000 poise (dynes-sec./cm.) in viscosity and more likely are less than 200 poise. (See, Van Wazer, Viscosity and Flow Measurement, lnterscience Publishers, New York (1962)). Consequently, such resins have a modulus of less than 1,000 dynes/cm. (at time of 1 second). Furthermore, experience with potting compounds has shown that the viscosity thereof must be less than about 200 poise in order to have a material which will easily flow between and envelope the ends of the closely spaced dent wires in a loom reed under theinfiuence of gravity. It is well known that the vast majority of thennoplastic resins of the type just described are inherently of low molecular weight and are linear (nongelled). The vast majority of such resins are also low in impact strength, in tensile and yield strength, in shear or tensile modulus, and in modulus of rupture. A thermoplastic polymer possessing the foregoing characteristics tends to be brittle, friable, rigid or nonflexible, and nonviscoelastic in nature. Thus, the vast majority of such easily pourable thermoplastic polymers are quite susceptible to chipping and cracking when impacted or vibrated. Moreover, at elevated temperatures (e.g., 100 F.), low molecular weight thennoplastics may readily soften and/or lose adhesion to the dent wires, thereby allowing the dent wires to loosen when subjected to continuous vibration and impact normally encountered in a loom.

The plastic adhesive material useful in the practice of this invention possesses a particular combination of modulus, elongation, and tensile strength properties that render such adhesive material very tough, durable, and impact resistant. Consequently, loom reeds prepared in accordance with this invention possess advantages which have not heretofore been provided.

SUMMARY OF THE INVENTION In accordance with the invention there is provided a loom reed comprising (a) a plurality of elongated dent wires disposed in spaced parallel relationship with respect to one another, and (b) frame members and dent wire spacing means consisting of flexible, extrudable thermoplastic adhesive which receives the ends of said plurality of dent wires, wherein said ends of said plurality of dent wires are adhesively secured in, firmly supported by, and maintained in spaced relationship by said frame members. The loom reed of the invention has a tough, nonfriable, durable frame which is very inexpensive and yet the frame securely holds the ends of the dent wires, serves as spacing means for the dent wires, and firmly supports them.

Because the frame members and dent wire spacing means consist of flexible, extrudable thermoplastic adhesive, the loom reed can withstand severe impact and continuous severe vibration without resulting cracking, chipping or permanent distortion of the frame members and without resulting misalignment or loosening of the dent wires. Consequently, the loom reed easily withstands bending, flexing and impact during manufacturing, shipping, storage, and use. Because the thermoplastic adhesive is flexible (i.e., viscoelastic in nature) and exhibits a plastic memory, the loom reeds may be rested or stored on end or edge for extended periods without resulting permanent bowing or distortion of the frames. The flexible, extrudable thermoplastic adhesive is also resistant to moisture, high humidity, and elevated temperatures normally encountered in a loom. Thus, the frame members maintain firm support and proper spacing of the dent wires under all conditions of use.

Because the frame members and dent wires spacing means are thermoplastic adhesive, the manufacture of the loom reeds is rapid, inexpensive, and uncomplicated. No resin molds or resin pouring operations are required, and mixing and curing of resins is eliminated. The flexible thermoplastic adhesive provides immediate support for the dent wires without having to wait for resin curing (as is the case with thermosetting resins) or hardening of liquid resin (as is the case with easily pourable thermoplastic resins). Repair or replacement of individual dent wires is also very convenient.

DETAILED DESCRIPTION OF THE INVENTION The invention is described in more detail hereinafter with reference to the accompanying di awings wherein like reference characters refer to the same parts throughout the several views and in which:

FIG. I is a plan view of a loom reed of the invention; and

FIG. 2 is an elevational view of the loom reed of FIG.

Referring to the drawings, there is shown a loom reed 10 comprising a plurality of elongated dent wires 12 disposed in spaced parallel relationship with respect to one another, and frame members 14 which adhesively secure and firmly support and anchor the end portions 16 of dent wires 12. The spacing of the dent wires may be the same or different. Frame members 14 comprise a flexible, extrudable, thermoplastic adhesive which adheres tenaciously to end portions 16 of dent wires 12 and thereby adhesively secure end portions 16 in the frame member and which maintains the proper spacing of end portions 16 of dent wires 12.

Frame member 14 may be an integral member or it may comprise more than one member. For example, end portions 16 of dent wires 12 may be disposed between two pieces of thermoplastic adhesive material which have been heated sufficiently to soften and adhere to end portions 16. In such a case the two pieces of adhesive material should flow between the dent wires sufficiently to be contiguous with each other so that no voids remain between the dent wires. Altematively, the dent wires are heated to a temperature above the softening point of the adhesive so that the adhesive will soften locally to envelope individual dent wires.

The thermoplastic adhesive frame 14 should soften sufficiently at high temperatures to flow between adjacent dent wires so that the dent wires will be very firmly and securely anchored within the frame and so that no voids remain between dent wires. Since the thermoplastic adhesive also maintains the correct spacing of the dent wires, the width and depth of the frame member should be sufficient to allow the end portions of the dent wires to be completely enveloped within the frame to be firmly supported thereby.

The thermoplastic adhesive material used in loom reeds of the invention must be flexible (i.e., it is viscoelastic in nature) and must exhibit an elongation of 20 to 1,000 percent and a tensile strength of 1,000 to 13,000 pounds per square inch (preferably 1,000 to 8,000 pounds per square inch). The adhesive material must also be very tough, i.e., the adhesive must be capable of absorbing energy and undergoing large deformations without rupturing. In order to obtain the proper balance of flexibility and toughness in the adhesive material, the thermoplastic adhesive must be extrudable (i.e., it has a modulus in the range of l X l0 to 5 X l0 dyneslcmf, and preferably 8 X 10 to 2 X 10 dyneslcmf). Thermoplastic adhesives which have the foregoing properties are tough and nonfriable. Consequently, such adhesives provide very durable, nonrigid frames for loom reeds. These adhesives also adhere tenaciously to the dent wires and prevent the development of moisture leakage paths which could result in rusting of the dent wires.

The cross-sectional shape of frame member 14 is not critical. For example, the cross-section may be semicircular, rectangular, or any other polygonal shape. The

frame members may also have a longitudinal channel provided in one surface thereof for receiving the end portions of the dent wires. Frame members 14 are most readily and efficiently provided by extruding the adhesive in the desired form or shape. Frame members 14 can also be provided by methods such as molding, calendaring, cutting of sheet stock, etc.

Suitable flexible, extrudable thermoplastic adhesives may be of any type so long as they exhibit an elongation of about 20 to 1,000 percent, a tensile strength of 1,000 to about 13,000 pounds per square inch, and a modulus of about 1 X to 5 X 10" dynes/cm. Such adhesives are commonly found within the following well-known polymer groups: polyamides, polyesters, polycarbonates, olefin polymers, olefinic copolymers, e.g., ethylene copolymers (e.g., ethylene/acrylic acid copolymer, ethylene/vinyl acetate copolymer), and modified ethylene copolymers (e.g., 80 weight percent ethylene/acrylic acid copolymer and weight percent polyurethane). Blends of thermoplastic adhesives are also very useful. Although a few specific useful adhesives may exhibit a viscosity of less than 1,000 poise when heated to 350 F. or higher, such occurrence is fortuitous, and by far the vast majority of these useful adhesives exhibit viscosities greater than 1,000 poise even when heated to 350-400 F.

The thermoplastic adhesive may contain various additives or fillers. For example, materials may be added to the adhesive to increase abrasion resistance or lubricity and fillers may be added to lower the cost of the adhesive or to improve its performance. Dyes or pigments may also be added to provide color.

EXAMPLE clamped tightly. The dent wires were then heated to a temperature above the bonding point of the adhesive bars (i.e., above about 300 F.) after which a pair of room temperature adhesive bars, disposed transversely with respect to the wires, were pressed against each end portion of the heated wires so as to embed the ends of the wires therein, leaving no voids between adjacent dent wires. The adhesive bars were then cooled to harden the adhesive surrounding the individual dent wires.

It is also possible to extrude the thermoplastic adhesive material directly onto the end portions of the dent wires in a continuous manner. The resulting loom reed structure is the same as that shown in the drawings.

Because the frame members and spacing means are thermoplastic adhesive, it is possible to conveniently remove or replace individual dent wires by heating the particular wire to be replaced to a temperature above the softening temperature of the thermoplastic frame whereby the particular dent wire may be pulled loose from the frame. Thus, repair or replacement can be accomplished conveniently and easily without disturbing the anchorage or spacing of the remaining dent wires.

What is claimed is:

l. A loom reed comprising:

a. a plurality of elongated dent wires disposed in spaced parallel relationship with respect to one another, and

b. frame members and dent wire spacing means consisting of flexible, extrudable thermoplastic adhesive which receives the ends of said plurality of dent wires,

wherein said ends of said plurality of dent wires are adhesively secured in, firmly supported by, and maintained in spaced relationship by said frame members.

2. The loom reed of claim 1 wherein said thermoplastic adhesive exhibits an elongation in the range of about 20 to 1,000 percent, a tensile strength in the range of about 1,000 to 8,000 psi, and a modulus in the range of 8 X 10 to 2 X 10 dynes/cm. I

3. The loom reed of claim 1 wherein said thermoplastic adhesive comprises an ethylene copolymer.

4. The loom reed of claim 1 wherein said thermoplastic adhesive comprises polyamide. 

2. The loom reed of claim 1 wherein said thermoplastic adhesive exhibits an elongation in the range of about 20 to 1,000 percent, a tensile strength in the range of about 1,000 to 8,000 psi, and a modulus in the range of 8 X 107 to 2 X 1010 dynes/cm.2
 3. The loom reed of claim 1 wherein said thermoplastic adhesive comprises an ethylene copolymer.
 4. The loom reed of claim 1 wherein said thermoplastic adhesive comprises polyamide. 